Observations on the balance in fish populations in a small reservoir in Ghana
Abstract
This paper examines the fish populations in a small reservoir located in the coastal savanna to the east of Accra, Ghana, to evaluate their balance. The main forage fishes were the cichlid. Sarotherodon galilaeus (E value 88.2%), and the prawn, Macrohrachium vollenhovenii (E value 7.8%). The carnivores were represented by the catfish, Glorias senegalensis, and the cichlid, Hemichromis bimaculatus, with E values of 2.6 and 0.2%, respectively. The F/C and Y/C ratios were 34.92 and 1.79, respectively, which suggests unbalanced populations, presumably due to overcrowding by stunted forage fish, mainly S. galilaeus. The AT value of 50.81 % , however, might suggest balanced populations, but this index may have been over-estimated and the populations may be incapable of producing harvestable crops.
